mmc: am654_sdhci: Add the quirk to set TESTCD bit

mmc: am654_sdhci: Add the quirk to set TESTCD bit

The ARASAN MMC controller on Keystone 3 class of devices need the SDCD
line to be connected for proper functioning.

In cases where this can't be connected, add a quirk to force the
controller into test mode and set the TESTCD bit. Use the flag
"ti,fails-without-test-cd", to implement this above quirk when required.

Additionally, this quirk also avoids waiting for the controller debounce
time.

This commit is similar to linux kernel commit c7666240ec76
("drivers: mmc: sdhci_am654: Add the quirk to set TESTCD bit").

Signed-off-by: Emanuele Ghidoli <emanuele.ghidoli@toradex.com>